| 摘要 |
An insert (10) for use in clothing designed to protect against bullets or knife attacks includes an upper layer (14) having a ceramic matrix. A pair of plugs (20) are fitted to the ceramic layer (14), the plugs (20) being made from a material having an impedance to vibration substantially the same as that of the ceramic matrix at the point of manufacture. The plugs (20) are configured for conducting mechanical vibration through the ceramic layer (14), for recording a vibration-related signature for the insert (10). By comparing a series of such signatures recorded over time, it is possible to assess whether the internal structure of the ceramic matrix has become damaged, which is useful in determining whether the insert needs to be replaced or repaired. |
